/*
Copyright 2002, QNX Software Systems Ltd. Unpublished Work All Rights
Reserved.

 
This source code contains confidential information of QNX Software Systems
Ltd. (QSSL). Any use, reproduction, modification, disclosure, distribution
or transfer of this software, or any software which includes or is based
upon any of this code, is only permitted under the terms of the QNX
Confidential Source License version 1.0 (see licensing.qnx.com for details)
or as otherwise expressly authorized by a written license agreement from
QSSL. For more information, please email licensing@qnx.com.
*/
/* lzo_mchw.ch -- matching functions using a window

   This file is part of the LZO real-time data compression library.

   Copyright (C) 1996-1999 Markus Franz Xaver Johannes Oberhumer

   Markus F.X.J. Oberhumer
   markus.oberhumer@jk.uni-linz.ac.at
 */




/***********************************************************************
//
************************************************************************/

typedef struct
{
	int init;

	lzo_uint look;			/* bytes in lookahead buffer */

	lzo_uint m_len;
	lzo_uint m_off;

	lzo_uint last_m_len;
	lzo_uint last_m_off;

	const lzo_byte *bp;
	const lzo_byte *ip;
	const lzo_byte *in;
	const lzo_byte *in_end;
	lzo_byte *out;

	lzo_progress_callback_t cb;

	lzo_uint textsize;		/* text size counter */
	lzo_uint codesize;		/* code size counter */
	lzo_uint printcount;	/* counter for reporting progress every 1K bytes */

	/* some stats */
	unsigned long lit_bytes;
	unsigned long match_bytes;
	unsigned long rep_bytes;
	unsigned long lazy;

#if defined(LZO1B)
	lzo_uint r1_m_len;

	/* some stats */
	unsigned long r1_r, m3_r, m2_m, m3_m;
#endif

#if defined(LZO1C)
	lzo_uint r1_m_len;
	lzo_byte *m3;

	/* some stats */
	unsigned long r1_r, m3_r, m2_m, m3_m;
#endif

#if defined(LZO1F)
	lzo_uint r1_lit;
	lzo_uint r1_m_len;

	/* some stats */
	unsigned long r1_r, m2_m, m3_m;
#endif

#if defined(LZO1X) || defined(LZO1Y) || defined(LZO1Z)
	lzo_uint r1_lit;
	lzo_uint r1_m_len;

	/* some stats */
	unsigned long m1a_m, m1b_m, m2_m, m3_m, m4_m;
	unsigned long lit1_r, lit2_r, lit3_r;
#endif

#if defined(LZO2A)
	/* some stats */
	unsigned long m1, m2, m3, m4;
#endif
}
LZO_COMPRESS_T;



#if defined(__PUREC__) && defined(__LZO_TOS16)
/* the cast is needed to work around a bug in Pure C */
#define getbyte(c) 	((c).ip < (c).in_end ? (unsigned) *((c).ip)++ : (-1))
#else
#define getbyte(c) 	((c).ip < (c).in_end ? *((c).ip)++ : (-1))
#endif

#include "lzo_swd.ch"



/***********************************************************************
//
************************************************************************/

static int
init_match ( LZO_COMPRESS_T *c, lzo_swd_t *s,
			 const lzo_byte *dict, lzo_uint dict_len,
			 lzo_uint32 flags )
{
	int r;

	assert(!c->init);
	c->init = 1;

	s->c = c;

	c->last_m_len = c->last_m_off = 0;

	c->textsize = c->codesize = c->printcount = 0;
	c->lit_bytes = c->match_bytes = c->rep_bytes = 0;
	c->lazy = 0;

	r = swd_init(s,dict,dict_len);
	if (r != 0)
		return r;

	s->use_best_off = (flags & 1) ? 1 : 0;
	return r;
}


/***********************************************************************
//
************************************************************************/

static int
find_match ( LZO_COMPRESS_T *c, lzo_swd_t *s,
			 lzo_uint this_len, lzo_uint skip )
{
	assert(c->init);

	if (skip > 0)
	{
		assert(this_len >= skip);
		swd_accept(s, this_len - skip);
		c->textsize += this_len - skip + 1;
	}
	else
	{
		assert(this_len <= 1);
		c->textsize += this_len - skip;
	}

	s->m_len = 1;
	s->m_len = THRESHOLD;
#ifdef SWD_BEST_OFF
	if (s->use_best_off)
		memset(s->best_pos,0,sizeof(s->best_pos));
#endif
	swd_findbest(s);
	c->m_len = s->m_len;
	c->m_off = s->m_off;

	swd_getbyte(s);

	if (s->b_char < 0)
	{
		c->look = 0;
		c->m_len = 0;
		swd_exit(s);
	}
	else
	{
		c->look = s->look + 1;
	}
	c->bp = c->ip - c->look;

#if 0
	/* brute force match search */
	if (c->m_len > THRESHOLD && c->m_len + 1 <= c->look)
	{
		const lzo_byte *ip = c->bp;
		const lzo_byte *m  = c->bp - c->m_off;
		const lzo_byte *in = c->in;

		if (ip - in > N)
			in = ip - N;
		for (;;)
		{
			while (*in != *ip)
				in++;
			if (in == ip)
				break;
			if (in != m)
				if (memcmp(in,ip,c->m_len+1) == 0)
					printf("%p %p %p %5d\n",in,ip,m,c->m_len);
			in++;
		}
	}
#endif

	if (c->cb && c->textsize > c->printcount)
	{
		(*c->cb)(c->textsize,c->codesize);
		c->printcount += 1024;
	}

	return LZO_E_OK;
}


/*
vi:ts=4
*/

